How strange is THIS?

I have a Canada goose that I got as a newborn gosling back in May (orphan/rejected). She has not been around other geese. I have chickens but she hates them and does not associate with them unless she is running them off.

This week, my daughter called me at work to tell me that she had laid an egg and was sitting on it in the yard. I was not thinking she was old enough to lay yet and it is not right time of year anyway from what I have researched so there is a chance that it was a chicken egg. Reportedly, she sat on the egg on and off throughout the day. When I came home, unfortunately the egg had been stepped on (goats or the pig, I suspect) and I could not really tell if it was a chicken egg or not.

Would a goose that young start to lay or if not how strange would it be for her to sit on a chicken egg. I am known for my weird and strange animals so it would not surprise me if this was bizzare...Anyone else have this situation or anything close to it?